CNS disorders nowadays concern large sections of the population. In particular on account of the increase in elderly people, the numbers of patients are increasing continuously.
Epilepsy is the most common neurological disorder, affecting about 1% of the population worldwide. Epilepsy describes a condition in which a person has recurrent seizures due to a chronic, underlying process. Epilepsy refers to a clinical phenomenon rather than a single disease entity, since there are many forms and causes of epilepsy. Using a definition of epilepsy as two or more unprovoked seizures, the incidence of epilepsy is estimated at 5 to 10 people per 1000. An essential step in the diagnosis and treatment of a patient with a seizure is to determine the type of seizure that has occurred. The main characteristic that distinguishes the different categories of seizure is whether the seizure activity is partial or generalized or unclassified.
For the general population there are approximately 20-70 new cases per 100,000 diagnosed each year with a 3-5% lifetime probability of developing the disease. The older established antiepileptic drugs (AEDs) phenytoin, carbamazepine, clonazepam, ethosuximide, valproic acid and barbiturates are widely prescribed but suffer from a range of side effects. Furthermore, there is a significant group of patients (20-30%) that are resistant to the currently available therapeutic agents. Since 1989 several new drugs have been launched, including felbamate, gabapentin, lamotrigine, oxcarbazepine, tiagabine, topiramate, vigabartrin, zonisamide and levetiracetam. While many of new AEDs show improved efficacies and side-effect profiles, about 30% of patients with epilepsy remain untreated. There is clearly a need for improved medication.